Ship-from-store and click-and-collect promise flexibility. In practice, they create stock chaos if inventory is not synchronised in real time between store, central warehouse and e-commerce platform. Retail turnover grew by 4.7% in 2024, but this digital expansion only works if you can deliver on what you promise — and most stockouts are not system failures, they are a lack of operational visibility. This guide gives you an 11-point checklist to audit your stock synchronisation and avoid selling what you do not have.
The mistake 30-40% of stores make
We see in INFOS projects that click-and-collect stockouts are not a software failure — they are stock physically sitting in the back-of-store warehouse but not recorded in the system, or a manual count that diverges from reality. The store says "we don't have it", the customer thinks it is a digital glitch, and you lose the sale and their trust.
Before implementing any synchronisation, map today's real stock flow. Pick one product category (e.g. T-shirts from one brand) and follow it for 5 days: how many units enter the store, how many sell at the counter, how many stay in the back-of-store warehouse, how many are returned, how many disappear without record. Document each point of entry and exit (receipt, sale, return, inter-store transfer, disposal). Identify where the system diverges from reality. Calculate the average time between a sale at the POS and the update in the central system — if it is more than 30 minutes, it is critical for omnichannel. Measure the click-and-collect stockout rate over the last 3 months.
Define allocation rules before synchronising
A unit in stock can go to five different destinations. If you do not have explicit rules, the system (or the store) decides at random, and the customer who wants to collect in 2 hours loses out to the one who wants delivery in 5 days.
Without clear allocation rules, omnichannel is not flexibility — it is chaos that looks like the technology's fault.
Define priority by business context. A regional food retail chain may prioritise in-store sale > click-and-collect > ship-from-store > transfer to another warehouse. A specialist clothing retailer may reverse it: click-and-collect > ship-from-store > in-store sale > central warehouse (because the customer who booked a collection is already waiting). An optician or hardware store may give top priority to online orders with scheduled collection, because scheduling is a commitment.
Then, configure the automatic allocation sequence in your management system (ERP or MAXIRETAIL). If the system cannot do this, you are asking for conflicts. Document the rule in plain English — it is not a technical detail, it is business policy. Test the rule with 10 hypothetical scenarios (e.g. 5 units in stock, 3 collection requests, 2 for delivery — who goes without?). Communicate the rule to the store team — they need to know why an order that arrived first may not be the first to be prepared. Review the rule every quarter — if 40% of collection orders arrive late, the priority is wrong.
Real-time synchronisation: choose the right architecture
Real time does not mean every 5 seconds. It means: when the till registers a sale, the e-commerce knows in under 2 minutes that the unit is no longer available.
| Architecture | Typical latency | Implementation cost | Stockout risk |
|---|---|---|---|
| Nightly batch (update every 24h) | up to 24 hours | Low | Very high — the e-commerce sells stock the store has already sold |
| Synchronisation every 30-60 min | 30-60 minutes | Medium | High — only acceptable for low-turnover categories |
| Real-time integration (API) | <2 minutes | Medium-high | Low — the system reacts immediately |
If you have stores with high turnover (food, seasonal clothing) or promotional campaigns, a nightly batch is insufficient. Choose synchronisation every 30 minutes as a minimum. Check whether your POS and your e-commerce have an integration API — if they do not, synchronisation will always be manual or delayed. Set up alerts: if the difference between stock at the POS and in the central system exceeds 5 units, a notification is triggered to the store manager. Test the synchronisation with a pilot product for 2 weeks — measure how many times the central system diverges from the POS. Document the acceptable latency for each category (e.g. drinks <5 min, clothing <30 min, books <2h).
Reserve stock at the moment of order — with a deadline
When the customer clicks "Buy" on the site, the stock must be immediately reserved — not merely "counted", but marked as unavailable to other customers. If you do not do this, two customers can buy the same unit. The reservation must have a deadline: if the customer does not pay within 30 minutes, the reservation expires and the stock becomes available again.
Configure in the e-commerce: automatic reservation at the moment of order, with a validity period (e.g. 30 minutes for payment). If the store does not have enough stock, the system automatically offers: collection in 48h (if available at another warehouse) or delivery in 3-5 days. Communicate the exact collection time to the customer — "ready for collection between 2:00 pm and 3:00 pm" is better than "tomorrow". Audit weekly: how many reservations expired without payment? If it is more than 15%, the deadline is too short or there are problems at checkout.
Prepare the store for fulfilment — space, staff, process
Ship-from-store is not just software. It is also physical space, staff and process. A store that cannot prepare 20 orders a day without compromising customer service will generate delays and complaints. Define a picking zone in the store — separate from the sales counter, with shelves or boxes labelled by order. Calculate capacity: how many orders per hour can the team prepare? (Typical: 8-12 orders/hour with 1 dedicated person.) If click-and-collect demand exceeds capacity, hire additional staff or redirect orders to the central warehouse.
Train the team: to differentiate sales stock, collection stock and delivery stock. To use barcodes to validate the order before handing it over to the customer. Install a notification system — when the order is ready, the customer receives an SMS or push (e.g. "Your order is ready for collection"). If the store has more than 5 simultaneous orders, use a visual board (a screen with a list of ready orders) to avoid confusion.
Every stock movement must be auditable
Every movement — in-store sale, in-store collection, delivery — must be recorded and auditable. The AT (Tax Authority) expects you to be able to justify each unit sold. Check whether your POS generates SAF-T with detail of each transaction (DL 28/2019). If you use MAXIRETAIL, confirm that each stock movement (sale, return, transfer) is recorded with date, time and user. Test the monthly SAF-T export — can you justify all stock differences between the system and the physical count? If you have multiple stores, check that each generates an independent SAF-T (each store is a separate tax entity).
Communicate with precision: "Available" is vague
The "visible" stockout is not when the stock runs out — it is when the customer sees that the site says "available" but the store says "we don't have it". It is the divergence between what the system promises and what the store delivers. On the site, show "Available for collection in 2h" (not just "Available") — the customer knows there is a timeframe. If stock is limited, show "Last 3 units" — it creates urgency and reduces the risk of overbooking. If the store does not have stock, offer automatic alternatives: "Available in Lisbon (collection in 24h) or delivery in 3 days". Confirm collection by SMS/email 2 hours beforehand — if the customer does not confirm, release the stock.
Audit checklist — 11 points
| Point | Verification | Status |
|---|---|---|
| 1. Stock visibility | Does the e-commerce show stock in real time (latency <2 min)? | ☐ |
| 2. POS-central integration | Does each sale at the POS update the central system automatically? | ☐ |
| 3. Allocation rules | Does the system know what the priority is (store vs. collection vs. delivery)? | ☐ |
| 4. Stock reservation | When the customer orders, is the stock immediately reserved? | ☐ |
| 5. Reservation deadline | Does the reservation expire if the customer does not pay within 30 minutes? | ☐ |
| 6. Picking zone | Does the store have a dedicated space to prepare orders? | ☐ |
| 7. Fulfilment capacity | Can the store prepare >80% of orders within the promised timeframe? | ☐ |
| 8. Customer notification | Does the customer receive an SMS/email when the order is ready? | ☐ |
| 9. SAF-T and auditing | Is each stock movement recorded with date, time and user? | ☐ |
| 10. Availability communication | Does the site say "Collection in 2h" (not just "Available")? | ☐ |
| 11. Stockout rate | Are fewer than 5% of orders cancelled due to lack of stock? | ☐ |
If 8 or more points are ticked, you have solid foundations for omnichannel. If fewer than 5, the priority is integration and synchronisation — the rest follows naturally.
Frequently asked questions
What are ship-from-store and click-and-collect?
They are omnichannel fulfilment models. Ship-from-store allows the physical store to send orders directly to customers. Click-and-collect allows the customer to buy online and collect in store. Both require rigorous stock synchronisation to work without stockouts.
Why do stores have click-and-collect stockouts?
According to the article, 30-40% of stores make the mistake of not synchronising physically present stock with what is recorded in the system. The stock may be in the back-of-store warehouse but not accounted for digitally, or the manual count may diverge from reality.
What is the acceptable latency for stock synchronisation?
It depends on the category. Real time means less than 2 minutes between a sale at the till and the update in the e-commerce. For high-turnover products (food, clothing), synchronisation every 30 minutes is the minimum. For low-turnover categories, 30-60 minutes is acceptable.
How should I define stock allocation rules?
Define explicit priorities by business context. For example: in-store sale > click-and-collect > ship-from-store. Configure these rules in your ERP or management system, test with 10 hypothetical scenarios and communicate them to the store team in plain English.
What is a stock reservation with a deadline?
When the customer buys online, the stock is immediately marked as unavailable (reserved). If the customer does not pay within the defined deadline (e.g. 30 minutes), the reservation expires and the stock becomes available again to other customers.
What is the first step to audit stock synchronisation?
Map today's real stock flow. Pick one product category and follow it for 5 days: how many units enter, sell, stay in the back-of-store warehouse, are returned or disappear. Identify where the system diverges from physical reality.
What fulfilment capacity should a store have for click-and-collect?
One dedicated person can typically prepare 8-12 orders per hour. Define a picking zone separate from the sales counter. If demand exceeds capacity, hire additional staff or redirect orders to the central warehouse.
Sources
- INE (Statistics Portugal) — Retail Trade Statistics and Turnover Indices, 2024 data
- CNPD (National Data Protection Commission) — Guidelines on Data Processing in Stock Management Systems and E-commerce
- IAPMEI (Agency for Competitiveness and Innovation) — Guides to Digital Transformation in Omnichannel Retail
- ISO/IEC 27001:2022 Standard — Information Security Requirements in Inventory Management Systems
- ENISA (European Union Agency for Cybersecurity) — Security Recommendations for API Integrations and Real-Time Data Synchronisation